1. Field of the Invention
The present invention relates to a scaling process system which optimally carries out a scaling process of an image, a video output apparatus and a replay apparatus.
2. Description of Related Art
There are various types of formats such as NTSC (National Television System Committee), PAL (Phase Alternating Line), high-vision, personal computer signal and the like for video signals. When video signals of such various types of formats are to be displayed in a display which has various numbers of pixels, there is a need to carry out a scaling process to convert the signal format in accordance with the number of pixel of each display.
Conventionally, as a between-pixel interpolation method which is a technique of scaling process of a digital video, for example, a linear interpolation method, a three-dimensional interpolation method, a spline interpolation method and the like are known. In these methods, pixels which are uniformly processed by an interpolation filter from neighboring pixels are added between the original pixels.
Further, in recent year, HDMI (High Definition Multimedia Interface) is widely used as a digital interface for video transmission between AV devices (for example, see JP2008-67024 and JP2008-78867). In HDMI, a CEC (Consumer Electronics Control) line which can send and receive data in both directions is standardized.
Conventionally, a plurality of cables for each signal of video, audio and control have been used for connection between devices. However, in HDMI, only one cable is used and the control signal is transmitted in both directions. Therefore, for example, by relaying the control signal to the output apparatus such as STB, DVD player and the like connected by HDMI from a display of a television receiver, the entire AV system such as a home theater can be operated by one remote controller.
When carrying out a scaling process between AV (Audio Visual) devices which are connected by CEC of HCMI such as a DVD recorder and a television receiver, for example, it is preferable to carry out the scaling process by using a device which can execute the between-pixel interpolation method in the highest performance among the devices.
However, because there is no unequivocal evaluation for superiority/inferiority of between-pixel interpolation methods, there is a problem that which of the DVD recorder or the television receiver has higher performance, that is, which of the devices is preferable for carrying out the scaling process cannot be determined.